Determination of trace lead in water samples by microsphere phase extraction-flame atomic absorption spectrometry

After reaction with 1-(2-pyridylazo)-2-naphthol(PAN) to form a hydrophobic complex and extraction into carbon tetrachloride phase with the existence of cosolvent acetone,lead in the carbon tetrachloride was determined by flame atomic absorption spectrometry.Finally,a microsphere phase separation extraction-flame atomic absorption spectrometry was developed for determination of lead in water samples.Various conditions affecting complex reaction and phase separation were optimized.Under the optimal experimental conditions,there was a linear relationship between absorbance and lead concentration in the range of 1.07-96 μg/L with the correlation coefficient of 0.998 3.Detection limit of this method was 0.63 μg/L.The relative standard deviation was 3.7% by determination of sample solution which contained 20.0 μg/L Pb for seven times.This method had been applied to the determination of lead in water samples.It was found that the results were consistent with those obtained by inductively coupled plasma atomic emission spectrometry with relative standard deviations(RSDs,n=7) of 4.1%-5.8% and recoveries of 95%-98%.